1. Field of the Invention
The present invention relates to a device for fixing lenses in the bezel rims of a spectacle frame allowing easy and repeated mounting and removal of these lenses into and from the frame. Such a possibility is attractive for clients who have to wear corrective lenses and wish to be able to change frames frequently: for example women wishing to adapt the appearance of their spectacle frame to their dress and make-up or men who prefer a classical style of frame at work but a light, wire-type, well attached frame for practising a sport. Similarly, it is not always easy to determine which frame will be most suitable for a child who has to become accustomed to wearing spectacles for the first time. Furthermore, certain people might wish to buy a new frame for solar lenses each year, according to the fashion, if they could transfer previously purchased solar lenses of high quality in terms of filtering capacity, hardness and parallelism.
2. Description of the Prior Art
In current practice, opticians insert lenses, which are normally bevelled at the edges, in the bezel of the frame rim and close this rim by connecting the two end rim grippers by insertion of a screw. To prevent subsequent problems, the optician tends to tighten this screw firmly, thus setting the lens all the more firmly in the bezel. He will even lock this screw, using a punch, between the edge of the screw head and the rim gripper.
In order to change his spectacle lenses, the user firstly has to have a suitable tool: screwdriver, small pincers and small vice. He then needs a certain amount of skill to sense when the gripping of the bezel rim is sufficient to hold the lens securely without the risk of chipping it, particularly if the bevelled edge of this lens is not inserted perfectly in the bezel of the rim.
In practice, it is found that users prefer the optician to perform these operations and this obviously rules out frequent changes of frames.
It is known that a joint composed of resilient material such as rubber or plastic can be inserted between the lens and the bezel rim: specifications EP 061 002, DE 2 039 085, DE 3 038 032, but it is essential for the grip of the lens in the bezel rim to be snug. Furthermore, these materials tend to crush over time (phenomenon of creep) and the hold can become loose.
The specification FR 2 270 611 relates to an adapter ring which is placed between the bezel rim and a corrective lens and allows corrective lenses to be exchanged on a given frame. This ring transforms the bezel, which is internally V-shaped, into a truncated cone shaped support in which a flat-edged lens is wedged. This device suffers from several drawbacks. Firstly, the position of the lens with respect to rotation relative to the frame is uncertain. Secondly, the edge of the lens is not protected during an exchange and it can be ruined by poor handling. In particular, owing to the principle of wedging in a truncated cone shaped support, the lens can easily be released from the frame due to an impact.